BOJ_18405 : 경쟁적 전염

Author: spring0913

week11/BOJ_18405(경쟁적 전염).java

@@ -0,0 +1,67 @@
+import java.io.*;
+import java.util.*;
+
+public class Main {
+
+    private static int[][] virus;
+    private static int N;
+    private static PriorityQueue<int[]> q;
+    private static boolean[][] visited;
+
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        StringTokenizer st = new StringTokenizer(br.readLine());
+        N = Integer.parseInt(st.nextToken());
+        int K = Integer.parseInt(st.nextToken());
+        virus = new int[N][N];
+        q = new PriorityQueue<>((o1, o2) -> Integer.compare(virus[o1[0]][o1[1]], virus[o2[0]][o2[1]]));
+        visited = new boolean[N][N];
+        for(int i=0; i<N; i++) {
+            st = new StringTokenizer(br.readLine());
+            for(int j=0; j<N; j++) {
+                virus[i][j] = Integer.parseInt(st.nextToken());
+            }
+        }
+        st = new StringTokenizer(br.readLine());
+        int S = Integer.parseInt(st.nextToken());
+        int X = Integer.parseInt(st.nextToken());
+        int Y = Integer.parseInt(st.nextToken());
+        for(int i=0; i<N; i++) {
+            for(int j=0; j<N; j++) {
+                if(virus[i][j] > 0 && !visited[i][j]) {
+                    visited[i][j] = true;
+                    q.offer(new int[]{i, j});
+                }
+            }
+        }
+        for(int i=0; i<S; i++) {
+            bfs();
+        }
+        System.out.println(virus[X-1][Y-1]);
+    }
+
+    public static void bfs() {
+        int[] dh = {0, 1, 0, -1};
+        int[] dw = {-1, 0, 1, 0};
+        List<int[]> nextVirus = new ArrayList<>();
+        while(!q.isEmpty()) {
+            int h = q.peek()[0];
+            int w = q.peek()[1];
+            q.poll();
+            for(int i=0; i<4; i++) {
+                int nextH = h + dh[i];
+                int nextW = w + dw[i];
+                if(nextH >= 0 && nextH < N && nextW >= 0 && nextW < N) {
+                    if(!visited[nextH][nextW]) {
+                        visited[nextH][nextW] = true;
+                        virus[nextH][nextW] = virus[h][w];
+                        nextVirus.add(new int[]{nextH, nextW});
+                    }
+                }
+            }
+        }
+        for(int i=0; i<nextVirus.size(); i++) {
+            q.offer(nextVirus.get(i));
+        }
+    }
+}